kyverno: include v2 reports in aggregate views

[nyxsky404]

Summary

• add a shared Kyverno report-source hook for PolicyReport, ClusterPolicyReport, EphemeralReport, and ClusterEphemeralReport
• switch Overview, Violations, ComplianceBadge, usePolicyResultCounts, and PolicyViewer to read the shared normalized source list
• allow aggregate report routes/actions when any supported report source exists, and bucket namespaced v2 report results by report namespace
• add regression tests for source merging and namespaced v2 report bucketing

Fixes #1135

Validation

• npx -y node@22 node_modules/.bin/headlamp-plugin lint
• npx -y node@22 node_modules/.bin/headlamp-plugin tsc
• npx -y node@22 node_modules/.bin/headlamp-plugin test
• npx -y node@22 node_modules/.bin/headlamp-plugin build
• Live Headlamp check on kind-lfx-headlamp with a temporary EphemeralReport: Violations showed Violations (4), Overview showed Fail: 4, the compliance badge showed 4, the matching policy row showed 1 / 1 failed, and PolicyViewer showed Associated Report Results (1).